Kepler 452b: NASA first announced the discovery of Kepler 452b, the most Earth-like planet discovered to date, on Thursday. But scientists believe there could be many more planets similar to Earth out there.

This artist's rendering made available by NASA on Thursday shows a comparison between the Earth, left, and the planet Kepler-452b. It is the first near-Earth-size planet orbiting in the habitable zone of a sun-like star, found using data from NASA's Kepler mission. The illustration represents one possible appearance for the exoplanet - scientists do not know whether the it has oceans and continents like Earth.

News that NASA's Kepler mission has discovered an Earth doppelgänger 1,400 light-years away thrilled the scientific and amateur astronomy communities. But recent research suggests that there may be many more similar discoveries of Earth-like planets to come.

As far back as 2013, astronomers reported that there could be as many as 40-billion Earth-sized planets orbiting around the habitable zones of sun-like stars within the Milky Way Galaxy alone. Now, new technologies are providing even more details about these lookalikes, opening the possibility that the existence of numerous Earth-like planets will soon be confirmed.

On Thursday, NASA announced that its planet-hunting mission Kepler had discovered the most Earth-like planet to date, the Kepler 452b. Its discovery, only 20 years after scientists proved definitively that stars other than the sun host planets, is considered a milestone in the search for other worlds.

“The new planet circles its sun-like star in an orbit that lasts 385 days, placing it firmly in the zone that scientists consider habitable – where temperatures are warm enough for there to be liquid water on the surface,” The Christian Science Monitor reported Thursday.

The Kepler Space Telescope has been compiling data on these “exoplanets” for six years, but scientists have been unable to explore the data in full.

“Now, thanks to improved techniques and automated technology, astronomers are able to go back through old, unexamined Kepler data and identify which of the thousands of identified planets may be Earth-like,” the Monitor reported. Scientists have asserted that it is the ability to examine old data, instead of the collection of new data, that will allow them to make new discoveries.

The data is providing details about which planets are similar to ours in age, temperature, and habitability. Potential planets require follow-up observations and reassessment to verify whether or not they are really planets.

John Grunsfeld, associate administrator for NASA’s Science Mission Directorate, says NASA is optimistic they’ll find another planet that even more closely resembles the Earth.

“It’s an unfolding story,” he told reporters during the conference call Thursday. “We’re getting closer and closer to finding a twin like the Earth.”